[HN Gopher] Novel color via stimulation of individual photorecep...
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Novel color via stimulation of individual photoreceptors at
population scale
Author : radeeyate
Score : 165 points
Date : 2025-04-20 02:03 UTC (20 hours ago)
(HTM) web link (www.science.org)
(TXT) w3m dump (www.science.org)
| K0balt wrote:
| What is meant by population scale in this context?
| turnsout wrote:
| It's jargon for "a lot of cones." 10^3 to be specific.
| K0balt wrote:
| Cool, thanks. I skimmed the article on how to introduce new
| colors to entire populations, that seemed like a really
| promising capability! lol.
| throwanem wrote:
| Very _Snow Crash,_ maybe. If I recall, the cyberdecks in that
| story used lasers to draw on the user 's retinas, rather than an
| HMD.
| NitpickLawyer wrote:
| Microsoft Research had a project like this at one point, with
| "goggles" that used lasers on your retina instead of LCDs to
| project images. No idea what happened to the project, as I
| haven't heard anything recently.
| corysama wrote:
| I swear I remember reading in the 80s about the Air Force
| having monochrome VR goggles consisting of a per-eye laser,
| magnetic oil lens for per-pixel depth focus, two perpendicular
| rotating mirrors for the raster scan and a curved glass lens to
| reflect and focus the raster scan on to the retina.
| fy20 wrote:
| Imagine walking through a shopping mall and suddenly having a
| Nike logo projected directly onto your retine, obscuring
| everything you see.
| Levitz wrote:
| "Welp, time for terrorism I guess"
| throwanem wrote:
| Yeah, I mean I haven't been to Vegas myself, but I've had
| pillow talk with some people who went.
|
| (All illuminated signage could be said to draw on one's
| retinas, after all. The major differences I see with this
| method beyond improved gamut are first that it rasters, and
| second that I think we have to worry what happens if it
| _fails_ to raster...)
| jonas21 wrote:
| > _Five subjects were recruited for this experiment ... Subjects
| 10001R, 10003L, and 20205R are coauthors on the paper and were
| blinded to the test conditions but were aware of the purposes of
| the study. The other two subjects were members of the
| participating lab at the University of Washington but were naive
| to the purposes of the study._
|
| Is it normal for the authors to experiment on themselves and
| their colleagues like this? Or did they not like the idea of
| laser-stimulating the photoreceptors of random strangers?
| pvg wrote:
| That is the tradition.
|
| _I tooke a bodkin gh & put it betwixt my eye & the bone as
| neare to the Backside of my eye as I could: & pressing my eye
| with the end of it (soe as to make the curvature a, bcdef in my
| eye) there appeared severall white darke & coloured circles_
|
| https://www.newtonproject.ox.ac.uk/view/texts/normalized/NAT...
| sebmellen wrote:
| Wow, I never knew that Newton risked retinal detachment to
| prove his theories.
| gnabgib wrote:
| Not a Neal Stephenson fan then? (The Baroque Cycle
| https://en.wikipedia.org/wiki/The_Baroque_Cycle)
| parpfish wrote:
| Also google "Giles Brindley" for another great self-
| experimentation tale
| krispyfi wrote:
| Also Albert Hofmann and Alexander Shulgin
| parpfish wrote:
| Self experimentation is pretty common in psychophysics
| experiments. I think a big part of it is that the experiments
| are long and boring, so the scientists themselves are the only
| people likely to pay attention and perform the task accurately
| the whole time.
| etrautmann wrote:
| Yes - many psychophysics experiments require a LOT of time and
| careful attention that would be tricky to get from random
| participants. It's often not at all an issue of safety or risk
| and more just the length, tedium, and motivation.
| robertclaus wrote:
| There is a theory that specific shades of colors are difficult to
| recognize or differentiate unless you name them. I wonder how
| unique these 100% saturated colors would look without context
| compared to other colors.
| qingcharles wrote:
| A great many languages don't differentiate between green and
| blue. There is simply one word for both.
| Muromec wrote:
| A great deal of languages only have one blue color
| carlosjobim wrote:
| Learning to see is a skill that we have to train. If you ever
| try to paint or draw a picture from a photographic reference,
| you will realize that you've spent your whole life blind. Even
| with the photo right in front of you, it can be extremely hard
| to paint certain details, because the brain simply refuses to
| accept the photographic reality when it has another idea of how
| an object should look.
|
| As for colour, language does not help very much with being able
| to see and understand them. What helps more is playing with
| photographic software and getting a feel for the relations
| within a system like HSL, or RGB.
| tianqi wrote:
| This story makes me remember that I had heard a fun fact a long
| time ago that many people have never actually seen the colour
| "violet" which is a single wavelength of visible light. Because
| there are very few things that reflect only this wavelength in
| reality. The purple colour we see is formed from a mixture of red
| and blue, whether it's something in nature, screen displaying or
| printing. I was so intrigued that I bought a 405nm laser torch
| and invited some friends to a home party to 'See the real
| violet'. That single wavelength of purple really made a different
| experience, and with good friends, we had a great day.
|
| The olo experiment was very interesting, and it told me that
| today we even have the technology to stimulate a single cone cell
| one by one in time. I know that we can't accurately display the
| olo on screen right now, which also prevents any of these
| articles from actually containing a picture of the olo. I think
| it's very close to #00FFEE, and I'm making it the colour of my
| Hacker News's top bar.
| tines wrote:
| > Because there are very few things that reflect this
| wavelength in reality.
|
| You mean few things that reflect only this wavelength? Because
| I would think anything white would reflect this wavelength just
| like any other.
| tianqi wrote:
| Yes, I meant reflecting only this wavelength. Thanks.
| subb wrote:
| You did send a specific wavelength to your retina, but that
| wasn't violet. Because violet is a construct by your brain.
|
| Color is not a property of wavelength. There's nothing special
| about photons wiggling in the 380 to 750nm range.
|
| In general it's not necessary to be this pendatic, but given
| the topic here, I think it's important to realize this. It
| takes a while because we are so good at projecting our internal
| experience outward.
|
| Remember the blue / black dress?
| tianqi wrote:
| In my personal conception, violet is the kind of colour at
| the lower edge of the rainbow, which is a single wavelength.
| And purple is what the brain constructs. However, of course,
| the names of the colours are themselves vague.
| bdelmas wrote:
| Hmm if you talk to a colorist violet and purple are 2
| different colors one more on the red and the other more on
| the blue. That's still the construct of 2 wavelength
| colors. So a made up color of our brain that doesn't exist.
| dleary wrote:
| "Violet" is a spectral color, which means that it is a
| color formed by a single wavelength of light. And it is a
| member of the rainbow (the spectrum).
|
| "Purple" is a mixture of red and blue.
| eviks wrote:
| > did send a specific wavelength to your retina, but that
| wasn't violet.
|
| It was, by definition
|
| > Color is not a property of wavelength.
|
| Sure, it's a label
|
| > There's nothing special about photons wiggling in the 380
| to 750nm range.
|
| There is - they activate different receptors your brain
| relies on, hence leading to a distinct (from other
| wavelengths) sensation
| subb wrote:
| The waves aren't inherently special, your retina is.
|
| What if we were sensitive to the 200 to 500nm range? What
| would be blue, violet and red then?
|
| Our eyes and brain are the one constructing what we
| perceive as color. It doesn't exists outside of us.
|
| Here's good article on the subject:
| https://anthonywaichulis.com/regarding-perception-
| photograph...
| Smithalicious wrote:
| >What if we were sensitive to the 200 to 500nm range?
|
| https://www.youtube.com/watch?v=A-RfHC91Ewc
| carlosjobim wrote:
| Violet is a real wavelength, below blue on the spectrum.
| Where it becomes invisible to the human eye, it starts
| getting called ultraviolet.
|
| Magenta and purples are constructs by the brain, as you
| mention.
| subb wrote:
| No, they are all constructed, including blue.
|
| If I shine some wavelength to your eyeball and you say "it
| looks blue", but then I change the surrounding and now it
| looks white, I don't think you would conclude that the
| original wavelength is blue.
|
| We have a many examples like this, which prescribe that
| vision is not at all an accurate wavelength measurement
| device.
| scotty79 wrote:
| How did you spread laser light over larger area?
|
| The idea I'm having right now is reflecting it off of the rough
| side of aluminum foil.
| tianqi wrote:
| I remember we just simply shone at a white wall.
| perilunar wrote:
| > The purple colour we see is formed from a mixture of red and
| blue, whether it's something in nature, screen displaying or
| printing.
|
| Well if it's on an RGB screen, or printed with CMYK inks then
| it's not 'real' violet, but there must be plenty of natural and
| artificial pigments that are actually reflecting violet light
| and not blue + red light. I imagine any pure compound would be
| doing this. E.g cobalt phosphate (aka cobalt violet).
|
| You could tell by illuminating a sample with different light
| sources. See metameric failure:
|
| https://en.wikipedia.org/wiki/Metamerism_(color)#Metameric_f...
| erik wrote:
| > many people have never actually seen the colour "violet"
| which is a single wavelength of visible light
|
| The violet seen in a rainbow (in nature, not a photo) is legit
| single wavelength violet. Same with the rainbows created from
| shining white light through a prism.
|
| It's true that you don't really get to see it in isolation very
| often though. Maybe some flowers, birds, or butterflies? Or
| maybe the purple glow you get from UV lights?
| phkahler wrote:
| Why is violet in the rainbow not a very blue color? I would
| think it only activates the blue cones. 405nm is a nifty
| color.
| jfengel wrote:
| Because the cone isn't really a "blue" cone, and neither is
| the "red" one. The curves overlap in complex ways. A pure
| violet photon also slightly stimulates the long wavelength
| cone.
|
| That's why red+blue=purple feels a bit like violet. It
| creates a similar double firing.
|
| (And why red plus green gives an even more accurate yellow.
| The long and medium cones have a lot of overlap.)
| GrantMoyer wrote:
| This is a common misconception, but the sensitivity of L
| cones ("red" cones) increases monotonically until about
| 570nm (monochromatic yellow), so violet light stimulates
| L cones the least out of all visible wavelengths of
| light. Magenta light, a mixture of red and blue
| wavelengths, stimulates L cones far more than violet
| light. See Wikipedia's LMS responsivity plot[1] or the
| cone fundamental tables from the Color & Vision Research
| Laboratory at [2].
|
| I think the misconception comes from plots of XYZ color
| matching functions[3]. The X color matching function
| indeed has a local maximum in the short wavelengths, but
| X doesn't represent L cone stimulation; it's a
| mathematically derived curve used to define the XYZ color
| space, which is a linear transform of LMS color space
| selected for useful mathematical properties.
|
| [1]: https://en.wikipedia.org/wiki/LMS_color_space#/media
| /File:Co...
|
| [2]: http://www.cvrl.org/
|
| [3]: https://en.wikipedia.org/wiki/CIE_1931_color_space#/
| media/Fi...
| carlosjobim wrote:
| It is technically the bluest color possible. What we
| perceive as true blue is different, and the brain has the
| weird imaginary magenta gradient between blue and red to
| confuse.
| _aavaa_ wrote:
| Meganta isn't imaginary, it's just non-spectral.
| carlosjobim wrote:
| It's imagined only in our minds, it fits the definition
| better than anything else.
| _aavaa_ wrote:
| First of all, all colors are imagined only in our minds.
|
| Second, the term imaginary color already exists, and it
| refers to a specific thing [0], and the colors on the
| line of purple are not one of them. What you are
| describing is a non-spectral color. They exist in day to
| day life and in nature, they simply do not have an
| associated wavelength.
|
| [0] https://en.wikipedia.org/wiki/Impossible_color
| carlosjobim wrote:
| What exactly are you trying to prove? The gradient
| between red and blue (magentas) are the only fully
| saturated colors that we can perceive, which aren't part
| of the electromagnetic spectrum. That's fantastic. Do you
| want to waste your life arguing about nothing instead of
| enjoying the miracles of nature?
| GrantMoyer wrote:
| Blue light looks different from violet light, because blue
| light activates M cones ("green" cones) more than violet
| light does.
| Nesco wrote:
| You can make the difference between a single wavelength color
| and a composite color which looks the same, by looking at
| objects nearby.
|
| If they are of one of the composite colors, they should appear
| in their natural hue
|
| Else they will just appear darker
| bitwize wrote:
| Violet is a true wavelength, and does occur in nature.
|
| Magenta, formed by mixing red and blue, does not exist in
| nature. For that reason, "magic pink" (full-brightness magenta,
| #ff00ff) is often used as a transparency color when the image
| format does not support an alpha channel (e.g., sprite sheets,
| Winamp skins).
| jameshart wrote:
| It's not true to say that mixtures of red and blue 'do not
| exist in nature'. Fuchsia petals really are that color. All
| you need is a substance that preferentially absorbs green
| wavelengths but reflects reds and blues.
|
| What 'does not exist in nature' is a single wavelength that
| produces the equivalent stimulation of your L, M and S cone
| cells as a mixture of red and blue light does.
|
| But most of what we see in nature is not single wavelength
| light - it's broad spectrum white light reflecting off things
| with absorption spectra.
|
| The reason stuff looks so weird under certain LED lights or
| pure sodium light is that the source light isn't broad
| spectrum - it's missing wavelengths already - so the way it
| interacts with absorption spectra is unintuitive. Something
| that looks blue under white light should still look blue
| under blue light - but a blue LED might just be emitting blue
| frequencies that the object absorbs, so it looks black
| instead.
| foota wrote:
| My shitpost is that they're lucky they didn't trigger a buffer
| overflow :-) but really, it doesn't seem completely out of
| question to me that it's possible that some unintended and
| serious consequence could occur from your brain receiving some
| stimulus that it doesn't naturally receive. I guess maybe there's
| no biological analog, but obviously bad things can happen in
| circuits, computers, etc., when this happens.
| ImHereToVote wrote:
| We can do this test on an ANN.
| braingravy wrote:
| The brain is remarkably resilient to that type of issue...
| Temporary buffer overflow (if you like) can be easily induced
| and observed with chemicals that modify function at the
| receptor level; Psychedelics being a classic example. (Worth
| noting there are many such chemicals used in medicine and
| research that induce overflow in function besides perception.)
|
| What I find fascinating is the neurological resilience that can
| be observed at cellular and behavioral levels to bounce back
| after an event like that.
|
| Non-chemical interventions, like adaption wearing special
| glasses that flip vision(1), are quickly accounted for by a
| healthy brain.
|
| 1:https://www.npr.org/2012/12/14/167255705/a-view-from-the-
| fli...
| OscarCunningham wrote:
| An easy way to percieve an oversaturated colour like this is to
| stare at one colour for a long time, and then switch to its
| complementary colour. The superposition of the colour and the
| afterimage of the same colour produces a more intense effect.
| Skgqie1 wrote:
| Your comment reminded me of an old short story:
| https://en.m.wikipedia.org/wiki/BLIT_(short_story)
| foota wrote:
| This is really fascinating to me. I'm amazed they're able to
| image the cells of the eye with sufficient resolution and speed
| to achieve this. From the paper, "and targeting 10^5 visible-
| wavelength laser microdoses per second to each cone cell.".
|
| If I understand correctly, they first use one type of
| spectroscopy (AO-OCT) to image the eye and build a map
| classifying the type of cells, and then use AO-SLO to find the
| positions of cells in real time. I assume that AO-OCT can't image
| at a sufficient rate for the second part (or they would just use
| one type?) so they need to first build this classification map,
| and then use it to match the position of cells to their type (e
| g., by overlaying the positions of cells with the classifications
| and making them line up).
| ratatoskrt wrote:
| The Guardian's article on this[1] includes a quote from an
| eminent colour expert at City:
|
| > The claim left one expert bemused. "It is not a new colour,"
| said John Barbur, a vision scientist at City St George's,
| University of London. "It's a more saturated green that can only
| be produced in a subject with normal red-green chromatic
| mechanism when the only input comes from M cones." The work, he
| said, had "limited value".
|
| [1]
| https://www.theguardian.com/science/2025/apr/18/scientists-c...
| codesnik wrote:
| identifying and shining light only on specific type of cells on
| retina through the iris is of limited value? I personally
| didn't know we even have that kind of precision.
| ratatoskrt wrote:
| It's just a typical response. What he means (in an admittedly
| unnecessary, snarky way) is that this is not going to
| revolutionise perceptual colour science. It's not going to be
| an out-of-this-world experience, nor will it change our
| understanding of how humans perceive colour. I personally
| think it's pretty cool, though.
| shermantanktop wrote:
| As a colorblind person, I look forward to you normies arguing
| over whether a dress is green or "super green."
| nkrisc wrote:
| Let's just settle it with a spectrometer.
| fouronnes3 wrote:
| Spectromers don't measure the subjective perception of color.
| nkrisc wrote:
| Of course, but trying to agree on the precise subjective
| perception of color is fruitless since no two people will
| perceive all wavelengths of visible light exactly the same.
| InsideOutSanta wrote:
| There are a bunch of "weird" colors that we don't see naturally.
| Wikipedia has a page on them:
| https://en.wikipedia.org/wiki/Impossible_color
|
| Some can be created at home without any special equipment. For
| example, you can't mix red and green and create a "redgreen," but
| if you cross your eyes and have one eye see red and the other see
| green, you might see a new color you haven't seen before.
|
| I also see weird colors in displays with a high frame rate that
| cycle between colors quickly. And at one point, I had a laser
| shot in my eye, which destroyed part of my vision. Initially, in
| that spot, I saw a weird iridescent silver-greenish color I had
| never seen before. Although that was pretty cool, I wouldn't
| recommend repeating this involuntary experiment just to see that
| color.
| soulofmischief wrote:
| Stygian blue is my favorite. What an insane color.
| dataflow wrote:
| I see it but it doesn't really feel like a new _color_? It
| just looks like blue on top of black. Maybe a new intensity,
| if I was being super generous, but not a new color.
| bigyabai wrote:
| I think it qualifies as a new color. If we can't
| differentiate colors on saturation, hue or intensity then I
| don't know how there are supposed to be multiple colors at
| all. It seems like fair play by the scientists, if a bit
| shrewd in defining "new".
| dataflow wrote:
| > If we can't differentiate colors on saturation, hue or
| intensity
|
| I don't think I follow. We can obviously distinguish all
| of these and do it on a daily basis... what do you mean
| we can't?
| InsideOutSanta wrote:
| To me, Stygian blue doesn't look like blue on top of black.
| It looks like black that glows blue, which doesn't make
| sense in the real world. I think it is fairly described as
| a new color--I would be quite unsettled if I encountered it
| in real life.
|
| Of course, colors are a hallucination our brain produces,
| so perhaps different brains deal differently with an
| unusual experience like Stygian blue.
| dataflow wrote:
| > It looks like black that glows blue
|
| I could maybe buy that as a description, but...
|
| > I think it is fairly described as a new color--I would
| be quite unsettled if I encountered it in real life.
|
| I don't feel this follows. There are a lot of things that
| would unsettle me if I saw them, like if someone gave off
| a visible aura. Heck, I even found a "black flame" a bit
| unsettling, and I saw a literal video of it on YouTube
| (look it up if you don't know what I'm referring to). I'd
| feel similarly if I saw a transparent human too. The
| feeling you get - or the fact that you haven't seen
| something visually similar before - doesn't really imply
| it's a new _color_ , I think!
| daveguy wrote:
| I get more of a black in the middle and blue glow around
| the edges. Also not sure it qualifies as a new color. To
| me, it's more like an interesting illusion that combines
| black and blue.
| eddd-ddde wrote:
| I tried really hard to see the "redgreen", but it just felt
| like an occlusion bug when two 3d objects have the exact same z
| layer and fight to render on top of the other.
| exe34 wrote:
| it should be called octarine, since it was brought forth by the
| magic of science!
| perihelions wrote:
| There's another ongoing thread about this paper,
|
| https://news.ycombinator.com/item?id=43736005 ( _" Scientists
| claim to have found colour no one has seen before
| (theguardian.com)"_ -- 27 comments)
| mppm wrote:
| Very cool!
|
| It would be cooler still if this technique could be used for
| future VR technology, creating full immersion by targeting all
| photoreceptors individually. But unfortunately... the optics of
| the eye does not actually allow individual cones to be fully
| isolated, as the spot size would be below the diffraction limit.
| They discuss this in Fig. 2 and the first section of the results.
|
| Even with a wide-open pupil and perfect adaptive optics, there
| would be 19% bleedover to nearby cells in high-density areas,
| while what they achieve in practice is 67% bleedover in a lower-
| density (off-center) area. This is enough to produce new effects
| in color perception, but not enough to draw crisp color images on
| the retina. :(
| thenoblesunfish wrote:
| I wonder if hallucinogens or other altered mental states can
| produce this effect, by inducing these sorts of internal signals
| that can't be created by input through the normal channels.
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